1. Field of the Invention
The present invention relates to a memory management device which operates to divide a memory into storage blocks so that the stored content is allowed to be erased only in blocks and a facsimile apparatus which is arranged to use the memory management device.
2. Description of the Related Art
Dynamic RAMs (DRAM) and static RAMs (SRAM) are representatively used as memories. The DRAM needs to periodically rewrite data even if it is powered on, while the SRAM operates to hold data only if it is powered on. Both of these memories fail to hold their data without their powers. These memories are required to have a spare battery for backing them up when the power is interrupted. On the other hand, the ROMs are capable of holding data if the power is off, while the ROM often has difficulty in rewriting data. The EPROMs are capable of rewriting data again and again only if ultraviolet rays are applied thereto. Regrettably, however, the EPROM is required to rewrite all the content stored therein. The EEPROM allows a program stored therein to be electrically erased. The program can be erased also in bits. Further, a kind of ROM called as a flash memory has been currently used. The flash memory has a capability of erasing the stored data in blocks, that is, block by block.
As mentioned above, nowadays, many kinds of memories have been commercially made available. Those memories have their merits and demerits. It is now desirous to provide such a memory as keeping the same ease of use as the DRAM or the SRAM and needing no power back-up. The DRAM or the SRAM is capable of easily changing a value of 1 or 0 at the current bit into a value of 0 or 1. On the other hand, the ROM keeps a value of 1 at any bit when it is in the initial state. If some data is written in the ROM, the values of 1 at the bits corresponding to the written data are changed to the values of 0. To return the 0""s to the 1""s, the ROM is required to do an erasing operation. Hence, unlike the DRAM, the ROM cannot easily change from the 0""s to the 1""s. For erasing the stored data, the EPROM enables to only erase all the data. The flash memory enables to erase the data only in blocks. Further, like the DRAM, the EEPROM has a capability of erasing the data in bits, that is, bit by bit. The EEPROM, however, is so expensive that it is not made available for general-purpose goods.
The present invention is designed to overcome the above-mentioned shortcomings, and it is an object of the present invention to provide a memory management device which achieves more efficient use of a memory whose data is erased only in each storage block and a facsimile apparatus which is arranged to use the memory management device.
In carrying out the object, according to a first aspect of the present invention, a memory management device provides a memory which enables to merely reverse the initial value at each bit and control means which operates to control the memory as considering the bit-by-bit reversed state from the initial state on the memory as a starting state.
According to a second aspect of the present invention, a memory management device provides a memory which operates to divide its storage area into blocks and erase the data only in a block-by-block manner, control means which sectionalizes the blocks according to the erasing condition of the information to be stored and store the information in the block having the corresponding erasing condition, and erasing means for erasing the stored content of the block only if the erasing conditions of all the stored informations about each block are met.
According to a third aspect of the present invention, a facsimile apparatus for temporarily storing the sending information or the received information in a memory and performing a series of operations containing sending or recording, provides the memory which operates to divide a storage area into blocks and erase the data only in blocks and storing means which operates to store the received information or the sending information in the sectionalized blocks if the information is to be stored in this memory.
According to a fourth aspect of the present invention, a facsimile apparatus for temporarily storing sending information and received information in a memory and then performing a series of operations containing sending or recording, provides the memory which operates to divide a storage area into blocks and erase the data only in blocks and control means which operates to read the data from the head of a group of empty blocks concatenated in a predetermined sequence if data is to be stored in one of the blocks of the memory.
According to a fifth aspect of the present invention, a facsimile apparatus for temporarily storing sending information or received information in a memory and then performing a series of operations containing sending or recording, provides the memory which operates to divide a storage area into blocks and erase the data only in blocks, storing means which operates to sectionalize the blocks for the sending information and the received information, and erasing means which operates to erase the sending information of one block when all the sending informations of the block are sent out or erase the received information of another block when a series of operations containing recording are done for all the received informations of the block.
According to a sixth aspect of the present invention, a facsimile apparatus for temporarily storing sending information or received information in a memory and then performing a series of operations containing sending or recording, provides the memory which operates to divide its storage area into blocks and erase the data only in blocks, erasing means which operates to erase the stored content of the memory in blocks, and control means which operates to couple the block whose content is erased by the erasing means to the tail of a group of empty blocks concatenated in a predetermined sequence.
According to a seventh aspect of the present invention, a facsimile apparatus for temporarily storing sending information or received information in a memory and then performing a series of operations containing sending or recording, provides the memory which operates to divide its storage area into blocks and erase the data only in blocks, erasing means which operates to erase the content stored in the memory in a block-by-block manner, and control means which operates to count the empty blocks if a sending or receiving operation is requested while the content of the block is being erased, perform the requested operation if it is equal to or more than the regulated number or keep to erase the data stored in the blocks until the number of actual empty blocks reach the regulated number, and then perform the requested operation.
According to an eighth aspect of the present invention, a facsimile apparatus for temporarily storing sending information or received information in a memory and then performing a series of operations containing sending or recording, provides the memory which operates to divide its storage area into blocks and erase the data only in blocks, erasure indicating means for indicating erasure of a block content, display means which operates to change the management data of an indicated block to the content of the block according to the erasing indication and display the erasing information of the block, and erasing means which operates to erase the content of the block whose management data is changed after the erasing information is displayed in the display means.
In the first aspect of the present invention, in the case of handling the memory, the memory is just allowed to be reversed from the initial state. Hence, the state reversed from the initial state in a bit-by-bit manner is used as a flag representing the starting state of the memory. This means that the initial state represents the waiting state.
In the second aspect of the present invention, the used memory operates to divide the storage area into blocks and erase the data only in blocks. Each block stores only the pieces of information having the same erasing condition. If the erasing conditions of all the pieces of information in the block are met, the informations in the block are erased. The informations having the same erasing condition often have a short period from when it is stored to when the erasing condition is met. On the other hand, if the pieces of information stored in one block have a different erasing condition rather than any other condition, a relatively long period is required until the erasing conditions of all the pieces of information stored in the block are met. By storing the informations having the same erasing condition in the same block, therefore, the content of the block is allowed to be quickly erased. The block is used for storing the new information. This serves to enhance the using effect.
In the third aspect of the present invention, in a case that the memory arranged to divide the storage area into blocks and erase the data in blocks is provided to the facsimile apparatus as a memory for storing the sending and receivied informations, if, at first, the sending or the receiving information is stored in one block, only the same type of information stored at first is stored in the block, so that both the received and the sending informations are not allowed to be stored in one block. If one kind of information is stored in one block and the other kind of information is stored in another block, the period taken when all the sending data in one block is sent or the period taken when all the receiving data in the block is recorded is shorter than the period if both kinds of data are stored in one block.
In the fourth aspect of the present invention, in a case that the memory arranged to divide the storage area into blocks and erase the data only in blocks is provided to the facsimile apparatus as a memory for storing the sending and the receiving informations, the empty blocks are concatenated in sequence for management so that the blocks are picked from the head one for storing the data therein. This makes it possible to evenly use all the blocks, thereby reducing the probability of failure in each block and hence prolonging the life of the memory.
In the fifth aspect of the present invention, in a case that the memory arranged to divide the storage area into blocks and erase the data only in blocks is provided to the facsimile apparatus as a memory for storing the sending and the received informations, either one of the sending information and the receiving information is stored in one block. If all the recorded sending informations are sent from the block where they are recorded, the data in the block is erased. On the other hand, when all the receiving informations are recorded in the block for recording only the received information, the overall information in the block is erased. In this state, the probability of establishing the erasing condition about all the informations in each block is higher than the probability given when both of the sending and the received informations are stored in one block. Hence, the period from when the data is stored in one block to when the data is erased from the block is reduced, thereby allowing the using ratio of the blocks to be enhanced.
In the sixth aspect of the present invention, in a case that the memory arranged to divide the storage area into blocks and erase the data only in blocks is provided to the facsimile apparatus as a memory for storing the sending and the received informations, if the erasing condition is met and the data is erased in blocks, the block whose content is erased is coupled to the tail of the empty blocks concatenated in the predetermined sequence. The blocks whose contents are erased are coupled in the erasing sequence. Hence, if the empty blocks are used, those blocks are allowed to be evenly used.
In the seventh aspect of the present invention, in a case that the memory arranged to divide the storage area into blocks and erase the data only in blocks is provided to the facsimile apparatus as a memory for storing sending and received informations, the erasing means operates to erase the block data if the erasing condition is met in the block. If the sending or receiving operation is requested while the block data is being erased, it is checked whether or not the number of empty blocks is equal to or more than the given number before the operation is executed. This makes it possible to secure storage of the regulated sending or receiving amount. If the number is less than the regulated number, the operation is executed to erase the data of the blocks whose erasing conditions are met until the number of the empty blocks reaches the regulated number. Then, the sending or receiving operation is executed.
Moreover, in the seventh aspect of the present invention, in a case that the memory arranged to divide the storage area into blocks and erase the data only in blocks is provided to the facsimile apparatus as a memory for storing the sending and the received informations, the received information may contain the information like a received message of an answering phone which is not permitted to be erased without judgement of a receiver. In this case, the erasure indicating means operates to indicate the erasure. In response to this indication, the display means operates to display the erasure of the block as keeping only the erasing management information of the block in the state that the block is erased. The erasing means operates to erase the content of the block. By this operation, an operator for indicating the erasure can quickly make sure that the erasure is done through the effect of the erasure indicating means. Hence, the operator does not need to wait until the actual erasure is done.